1991 Buick Parkave Lugnut Size

I was wondering what the bolt pattern and all that stuff is for this year and the 1992 model. I heard that it is 5X115 with and offset range of 34-45. I was wondering, and i know its sounds silly but just flatter me, if 18" rims would fit and turn smoothly without problems. Please help me out! thank you. :)

And also, what size tires would i need to make those fit comfortably, thanks.

Your PA does indeed have the 5X115mm pattern, the same as the GPX in the pic below with 18" wheels and 275X40X18 tires. If they work on the Bonnie, they should work on the PA :smokin:
http://img152.imageshack.us/img152/5718/2005bonneville82sf1.jpg